Why 10,000 steps might save your life

John Thyfault, professor of nutrition and exercise physiology at the University of Missouri.

Jacob FenstonKBIA

Everyone knows exercise helps you lose weight, build up muscles, and fit in the swimsuit next summer. But why, exactly, does it lower your risk of diabetes? In this Health & Wealth update, MU researchers look into the relationship between inactivity and spikes in blood sugar that can lead to type 2 diabetes and heart disease.

The chain of events might seem obvious: not getting enough exercise leads to gaining weight; being overweight increases the risk of a long list of health problems, from heart disease and diabetes to high blood pressure and high cholesterol.

But there is evidence that physical activity has a direct and immediate effect on the body, independent of burning calories or shedding pounds.

"There's literally thousands of things going on in your body when you exercise that you do not see in the mirror," said John Thyfault, one of the researchers. "Your body was designed to be physically active. And when we're inactive, it causes disruptions in the way our body works."

Thyfault wanted to find out how physical inactivity affects post-meal blood sugar spikes, which can increase the risk of diabetes and heart disease. To see the effects of inactivity in real time, the research team recruited 12 healthy, highly active volunteers, and made them sit still.

First, to measure the subjects' normal activity level, they had to wear pedometers and glucose monitors for seven days, while going about their usual daily routine and eating normal meals. Then, for three days, they did the same thing, but scaled way back on their activity level, walking less, and sitting more.

Many experts say to get enough exercise, you need to take 10,000 steps per day, roughly five miles. But on average, Americans take half that many steps. So the MU team had the volunteers, who averaged close to 13,000 a day normally, scale back to the average level of 5,000 steps.

In just three days of this sedentary lifestyle, participants' post-meal blood sugar spikes where much bigger-- as much as double in magnitude.

The takeaway?

"This data shows you need to get a certain threshold of activity every day," said Thyfault. But he acknowledged some days it's impossible to fit in any exercise routine. "Even when you have those days, take five minutes, take ten minutes, go for a walk, go move around your building. Get up, stand up, move around. You cannot just completely be sedentary all the time. It has pathological consequences on our body."

The study was published in the February edition of Medicine & Science in Sports & Exercise.